ext4: fix trimming of a single group

When ext4_trim_fs() is called to trim a part of a single group, the
logic will wrongly set last block of the interval to 'len' instead
of 'first_block + len'. Thus a shorter interval is possibly trimmed.
Fix it.

CC: Lukas Czerner <lczerner@redhat.com>
Cc: stable@kernel.org
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index d47a80e..21ee30b 100644 (file)
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -4860,7 +4860,7 @@ int ext4_trim_fs(struct super_block *sb, struct fstrim_range *range)
                if (len >= EXT4_BLOCKS_PER_GROUP(sb))
                        len -= (EXT4_BLOCKS_PER_GROUP(sb) - first_block);
                else
-                       last_block = len;
+                       last_block = first_block + len;
 
                if (e4b.bd_info->bb_free >= minlen) {
                        cnt = ext4_trim_all_free(sb, &e4b, first_block,